Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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E 2980 PCT
Use of Phyllanthus for treating chronic inflammatory
and fibrotic processes
The present invention relates to the use of
Phyllanthus for preventing or treating connective
tissue proliferations, for maintaining the level of
reduced glutathione, for inhibiting the
lipopolysaccharide (LPS)-induced nitric oxide synthase
(NOS) and for inhibiting the expression of the
cyclooxygenase (COX-2) protein.
Phyllanthus embraces a widespread group of
plants native to Central and South India, Taiwan, and
areas of Central and South America. The term
Phyllanthus means for the purpose of this invention all
representatives of the botanical family of Phyllanthus,
such as Phyllanthus niruri or, in particular,
Phyllanthus amarus etc. The treatment of a large number
of disorders with Phyllanthus is known in Indian folk
medicine. Thus, for example, the author of "Doctor K.M.
Nadkarni's Indian Materia Medica (3rd edition; revised
and enlarged by A.K. Nadkarni)" reckons in volume I
that the plant is known to be deobstruent, diuretic,
astringent and cooling. Likewise, compositions with
Phyllanthus are described for treating jaundice,
dropsy, gonorrhoea, menorrhagia and other impairments
of a similar type relating to the urogenital tract.
Also known are the use of the sap from the trunk mixed
with oil as ophthalmologicals or administrations for
ulcers, wound sites and swellings etc., as well as the
leaves for treating pruritus or other skin impairments.
There is also known to be a large number of
active substances which can be isolated from Phyl
lanthus, phyllanthin, hypophyllanthin, triacontanol,
triacontanal, repandusinic acid A (see, for example,
JP 03206044 A; AIDS-Res-Hum-Retroviruses (11/1992),
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English_translation as_corrected.doc
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vol. 8 (11), HIV-1 reverse transcriptase...),
phyllanthostatin-1, phyllanthoside, phyllanthocin,
phyllanthocin acid (see, for example, EP 173 4480;
US 4,388,457), phyllamycin A, B and C, retrojusti- -
cidin B, justicidin A and B (see, for example,
AIDS-Weekly, 25.9.95, AIDS Therapies Extracts ...),
linoleic acid, linolenic acid and ricinoleic acid (see,
for example, Journal of the American Oil Chemists
Society edition 81.06.00, ricinoleic acid in
Phyllanthus niruri ...), phyllamyricin D, E and F,
phyllamyricoside A, B and C (see, for example, J. Nat.
Prod. (11/1996), vol. 59 (11), Six lignans from ...),
putranjivain A (see, for example, Chem. Pharm. Bull.
(Tokyo), (04/1995), vol. 43 (4), Inhibitory effects of
Egyptian ...), ursulic acid and niruriside (see, for
example, J. Nat. Prod. 02/96, vol. 59 (2), Niruriside,
a new HIV ..., Rec. Trav. Chim. (06/1996), Synthesis of
...).
Therapeutic effects and administrations dis-
closed to date are an age-retarding effect (see, for
example, JP 08176004), prevention and therapy of
immunodeficiencies such as AIDS, influenza, colds,
tuberculosis, hepatitis, cirrhoses (see, for example,
US 5,529,778; AIDS-Weekly-Plus of 05.08.96, Antiviral
(Drug Development); Inhibition of HIV ...), antineo-
plastic effect (see, for example, US 4,388,457),
therapy of HIV, HBV and/or HCV infections, especially
topical treatment of Kaposi's sarcoma (see, for
example, EP 1734480; US 5,466,455), effect as protease
inhibitor, elastase inhibitor and as bleach (see, for
example, JP 09087136), analgesic and antiinflammatory
effect, effect as tyrosinase inhibitor (see, for
example, JP 08012566) and a use as disinfectant in
combination with extracts from other plants. Moreover,
uses in cosmetic preparations are also known. It is
evident from this large number of different areas of
administration and isolated active substances that
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Phyllanthus is a thoroughly well-known group of
medicinal plants employed for a large number of
indications and complaints.
One pathological phenomenon which appears to be _
responsible for a large number of other complaints is
so-called oxidative stress. By this is meant the stress
on the living cell through accumulation of toxic
oxidized compounds, such as lipid hydroperoxides,
hydrogen peroxide, singlet oxygen, hydroxyl/hyperoxide
anions. It is moreover possible for the stress to arise
through free radicals which are produced locally or
supplied from outside, especially so-called reactive
oxygen species (ROS) or peroxonitrite free radicals
etc. The oxidative stress can also be induced, for
example, by exposure to radiation, xenobiotics, heavy
metal ions or ischaemia/reperfusion (temporary
interruption of the blood supply to an organ). In the
latter case there is copious formation of hyperoxide
anions by xanthine oxidase, one of the oxidases of
about 300 kD and belonging to the flavoproteins, which
catalyses the breakdown of purines, because its natural
electron acceptor is oxygen. Under physiological con-
ditions, these hyperoxide anions are deactivated by
superoxide dismutase, but on reperfusion it has been
demonstrated that this involves production of large
amounts of oxygen free radicals.
Oxidative stress plays an important part in the
development of a number of acute and, in particular,
chronic disorders, for example inflammations of various
types, microangiopathies, fibrosis, rheumatoid
arthritis and other rheumatic disorders,
arteriosclerosis (LDL oxidation), tumour development
and progression, possibly Alzheimer's disease, but also
drug-induced acute damage such as paracetamol damage to
the liver.
The liver moreover plays, as central dynamic
organ of the body, an important part in a large number
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of the physiological and microphysiological processes
mentioned, the metabolic activities of the liver
(intermediary metabolism) being of crucial importance
on the one hand for supplying other organs but also, on
the other hand, for the chemical conversion
(biotransformation) of pharmaceutically active
substances (see Pschyrembel, Klinisches Worterbuch, de
Gruyter Verlag, 1986, pp. 935-937). The phenomenon of
oxidative stress which has already been described is
likewise for the most part combated by the body in the
liver. This contains a reservoir of diverse reduced
compounds of antioxidants, for example L-ascorbic acid,
carotenoids, dihydrolipoic acid, uric acid, glutathione
or cc-tocopherol, and prevents the occurrence of
reactive free radicals by means of various enzyme
activities (for example superoxide dismutase,
peroxidases such as glutathione peroxidase, catalase,
etc.).
Oxidative stress also has in particular adverse
effects on a large number of functions of liver tissue.
Liver tissue frequently responds to this with
connective tissue proliferation, which favours further
progression of permanent liver damage, such as, for
example, the development of a liver tumour. In this
connection, bile acids in particular are involved in
the pathogenesis of the hepatotoxic effect. Pronounced
damage to the liver leads stepwise via the development
of burn wounds to complete death thereof and thus to
death of the organism.
In all the abovementioned disorders, the
balance between oxidative stress and the defence
systems of the cells and organs have crucial
importance. It is therefore of crucial prophylactic and
therapeutic importance on the one hand to protect the
healthy liver from oxidative stress and, on the other
hand, to strengthen the diseased liver so that it is
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able permanently to overcome pre-existing oxidative
stress.
Compounds with a hepatoprotective activity have
in some cases considerable disadvantages because they
cannot be used if the liver is already diseased,
because the toxicity is too high.
The present invention is therefore based on the
object of providing substances which act on the liver
and have both a prophylactic and a therapeutic effect.
The present invention relates to the use of
Phyllanthus for preventing or treating connective
tissue proliferations, in particular fibrotic changes
for example of the liver, of the lung, of the kidney,
of the pancreas, of the intestine, of endocrine organs,
of the spleen, of the male or female urogenital tract,
of the joints, for example as a consequence of chronic
inflammatory processes such as, for example, rheumatoid
arthritis or chronic cardiomyopathies, and of
cirrhoses, an advanced stage of fibroses.
The use according to the present invention is
therefore particularly preferable for fibroses and
cirrhoses, preferably fibrosis of the liver and
cirrhosis of the liver. In this connection in
particular chronic inflammatory states lead to tissue
atrophy and pronounced scar formation with progressive
loss of function of the organs. An inhibition or
prevention of the connective tissue proliferation
therefore leads to less pronounced scar formation and
retention of the ability of the organs to function.
The corresponding activity of Phyllanthus in
preventing or improving in particular fibrosis of the
liver presumably derives from an antioxidative effect,
fibroses of the liver frequently being caused by viral
infections. Thus, for example, all the known hepatitis
viruses (hepatitis A, B, C, D, E and probably also G)
have a pronounced tropism for liver cells. It is to be
assumed that even the antiviral medicines currently
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used in medicine lead not to elimination of viruses but
only to suppression of virus replication (virus
suppression). Even if the virus disappears from the
peripheral blood (below the detection limit), the virus
is often still detectable in liver tissue. Thus,
Phyllanthus can exert an advantageous effect on liver
regeneration through its prophylactic and therapeutic
effect. This contributes to reducing chronic
inflammatory processes, with a reduction in the
developing connective tissue proliferation in the
liver. No medicines which can intervene in such an
early step of degenerative development have yet been
disclosed.
The present invention further relates to the
use of Phyllanthus for maintaining the level of reduced
glutathione. It has surprisingly been found that
Phyllanthus extracts have potent activity in the
maintenance of the level of reduced glutathione, which
occurs in particular in the liver. In these experiments
it was found that, in the functional cells of the liver
(hepatocytes) showing increased lipid peroxidation due
to t-butyl hydroperoxide, an extract of Phyllanthus not
only suppresses further lipid peroxidation but even
almost completely abolishes endogenous lipid
peroxidation. In comparative experiments with untreated
hepatocytes, a clear increase in the reductive capacity
was found, which suggests improved maintenance of the
intracellular level of reduced glutathione.
In preferred embodiments, Phyllanthus is used
to reduce the expression of smooth muscle alpha-actin
(SMA) mRNA and SMA protein. In a fibrotic liver, which
has an increased rate of cell division, there is
accumulation of extracellular matrix. The increased
amounts of extracellular matrix are regarded as crucial
for further progression of fibrosis of the liver as far
as cirrhosis of the liver. The accumulation of
extracellular matrix derives from activation of
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specific liver cells, the hepatic stellate cells (HSC),
which in activated form are referred to as activated
HSC. Compared with non-activated HSC, activated HSC
produce larger amounts of smooth muscle alpha-actin
(SMA) mRNA and protein, which is why the activation of
HSC can be measured from the expression of SMA. It has
now been surprisingly found in a series of experiments
that HSC lead, after treatment with Phyllanthus
extracts, to distinctly smaller amounts of extractable
SMA mRNA and SMA protein. In addition, HSC treated with
Phyllanthus extracts showed a distinct inhibition of
cell growth, which underlines the activity of
Phyllanthus extracts in these experiments. This means
that there is a possibility of converting activated HSC
as occur in fibrotic liver back into non-activated HSC,
thus favouring a regression of fibrosis of the liver.
The present invention further relates to the
use of Phyllanthus for inhibiting lipopolysaccharide
(LPS)-induced nitric oxide synthase (NOS), particularly
preferably inhibiting the induced nitric oxide synthase
(iNOS), and the use of Phyllanthus for inhibiting the
expression of cyclooxygenase (COX-2) protein.
LPS is a collective term for conjugates
composed of lipid and polysaccharide portions. The LPS
occurring in the outer membrane of the cell wall of
Gram-negative bacteria are composed in principle of
three components, namely lipid A, the core
oligosaccharide and the 0-specific side chains. Lipid A
anchors the LPS in the bacterial cell wall and is also
responsible for the immunoactivating effect of
bacterial cell wall constituents.
The expression of iNOS and COX-2 can be induced
in liver cells with the aid of LPS, which is why the
stimulated cells can be used as model systems for
fibrotic liver cells in which the expression of these
two proteins is likewise raised. Both iNOS and COX-2 is
known as a potent mediator of inflammatory processes
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like those occurring with degenerative changes of the
liver. It has now surprisingly been found in
comparative experiments that liver cells stimulated
with LPS and then treated with Phyllanthus extracts
showed a marked reduction in the rates of expression of
the iNOS protein and the COX-2 protein.
This invention) further comprises the use in one
of the abovementioned ways, using a fraction isolated
from Phyllanthus. An isolated fraction means in this
sense a subsidiary amount of Phyllanthus substances
which has been removed, for example, by chromatographic
means, distillation, precipitation, extraction,
filtration or in other ways from Phyllanthus. It means
in particular extracts and the fractions removed
therefrom by chromatography, distillation,
precipitation or extraction.
Another use according to the invention
comprises uses in accordance with one of the above-
mentioned examples, in which one or more chemical
substances, in particular active substances, isolated
from Phyllanthus are used. By these are meant in
particular also single substances isolated from
Phyllanthus extracts or other extracts, so-called
natural substance isolates, as are also known, for
example, from the prior art . The use of these isolated
active substances has the advantage that it is
generally necessary to use considerably smaller amounts
of substance and, moreover, more specific effects are
often achieved than with whole extracts or tablets.
In preferred uses according to one of the use
forms according to the invention, Phyllanthus is selec-
ted from individual members of the Phyllanthus family,
from the group of Phyllanthus amarus, Phyllanthus
niruri, Phyllanthus emblica, Phyllanthus urinaria,
translator's note: In the German text, it reads "Verbindung", which means
"compound".
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Phyllanthus myrtofolius Moon, Phyllanthus maderas
patensis and/or Phyllanthus ussuriensis.
In the uses according to the invention it is
possible to use leaves, bark, flowers, seeds, fruits, _
stalks, branches, trunk, root and/or wood of
Phyllanthus, preferably the herb, that is to say all
above-ground parts of the plant. It is moreover pos-
sible for Phyllanthus to be used in comminuted form
and/or in unmodified form, that is to say as whole
leaf, as granules, powder, precipitate, extract, dried
extract and/or exudate, with extracts or dried extracts
being preferred.
The preparation of Phyllanthus for the use
according to the invention comprises the preparation of
Phyllanthus powder or granules from one of the above
mentioned plant parts, extraction from plants, comminu-
ted plant parts, powders, and residues which have
already been treated previously with other solvents,
with hexane, water, methanol and/or other alcohols.
This also includes filtration and vacuum evaporation in
order to obtain a dried extract. Another method
comprises multiphase extraction with aqueous and/or
alcoholic and/or polar solvents. Also usual is filtra-
tion, for example through cellulose filters, precipi-
tation, preferably using ethanol, or separation by
ultracentrifugation, and maceration. It is moreover
always possible to operate at elevated or reduced
temperatures.
It is particularly preferred here to use
Phyllanthus in the form of an aqueous, nonpolar or
alcoholic extract, the alcoholic extract being carried
out preferably with short-chain (C1 to C4) primary
alcohols or mixtures thereof, especially methanol or
ethanol, the nonpolar one with (C5-C10), branched or
unbranched, chain hydrocarbons, or mixtures thereof,
especially with n-hexane.
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Also suitable as extractants are ethyl acetate
or appropriate organic solvent/water mixtures, prefer-
ably methanol/water mixtures or ethanol/water mixtures.
A suitable extraction process is disclosed, for -
example, in US Patent No. 4,673,575 or US Patent
No. 4,937,074.
In uses according to the invention, Phyllanthus
is preferably employed in the form of one or more
medicinal products (see Romp, Lexikon Chemie,
Version 1.4), such as an infusion solution, injection
solution, tablet, granules, ointment, medicinal pack,
enemas or in the form of one or more foodstuffs/food
supplements. These embrace the usual medical and
therapeutic applications and, in particular, also those
as food supplements, it being possible to use
Phyllanthus in these cases for prophylaxis and as
functional antioxidant which is a natural and non
hazardous addition to foodstuffs and, moreover, shows
the therapeutic and functional preventive effects
mentioned.
The use of Phyllanthus in the uses according to
the invention can take place orally, topically and/or
parenterally.
In a preferred embodiment, one or more other
active substances and/or suitable additives and/or
auxiliaries are used in addition to Phyllanthus. The
term active substance means for the purpose of this
invention therapeutically active substances such as,
for example, vitamin C or tocopherols, especially
ot-tocopherol, which are known as antioxidants or as
active substances against oxidative stress, and, for
example, antiinflammatory substances. These also
embrace therefore so-called combination products with
Phyllanthus. It should also be noted in this connection
in particular that the uses according to the invention
are by no means confined to only one form, fraction or
isolated active substance from Phyllanthus in each
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case, and it is also possible to use different forms
and/or fractions and/or isolated active substance from
Phyllanthus for a use.
Auxiliaries and additives mean for the purpose
of this invention substances which are known to be
added for therapeutic applications or as application
for food supplements in order to permit or facilitate a
corresponding use, for example adjuvants, disintegrants
and lubricants, bulking agents, buffers, preservatives,
stabilizers etc.
The following examples and figures are intended
to describe the invention in detail without restricting
it. These show:
Figure 1 the results of radical scavenger
experiments with 1,1-diphenyl-2-picrylhydrazyl (DPPH)
and the Phyllanthus extracts according to the
invention;
Figure 2 the results of radical scavenger
experiments with DPPH and vitamin C as comparison;
Figure 3 the results of radical scavenger
experiments with DPPH and a-tocopherol as comparison;
Figure 4 the results of radical scavenger
experiments with 3-[4,5-dimethylthiazol-2-thiazol-2-
yl]-2,5-diphenyltetrazolium bromide (MTT) and the
Phyllanthus extracts according to the invention;
Figure 5 the results of radical scavenger
experiments with MTT and vitamin C as comparison;
Figure 6 the results of radical scavenger
experiments with cytochrome and the Phyllanthus
extracts according to the invention;
Figure 7 the results of radical scavenger
experiments with cytochrome and vitamin C as
comparison;
Figure 8 the results of radical scavenger
experiments with sodium 3,3'-[1-
[(phenylamino)carbonyl]-3,4-tetrazolium]-bis(4-methoxy-
6-nitro)benzenesulphonic acid hydrate/phenazine
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methosulphate (XTT/PMS) and the Phyllanthus extracts
according to the invention;
Figure 9 the results of radical scavenger
experiments with XTT/PMS and vitamin C as comparison; -
Figure 10a-c the effect of Phyllanthus extracts on
liver cells (hepatocytes);
Figure 11 the inhibiting effect of Phyllanthus
extracts on the LPS-induced expression of NOS on the
basis of reduced NO production;
Figure 12 the inhibiting effect of an
ethanol/water extract of Phyllanthus on LPS-induced
iNOS expression;
Figure 13 the inhibiting effect of a hexane
extract of Phyllanthus on LPS-induced COX-2 expression;
and
Figure 13 the inhibiting effect of an
ethanol/water extract of Phyllanthus on LPS-induced
COX-2 expression;
Example 1:
Preparation of a dried extract according to the
invention
(fraction 1; lot No.: 9810H)
2 kg of the herb of a Phyllanthus amarus culti
vated in Madras, India, were converted into 450 g of
powder. These 450 g of powder were distilled in a
Soxhlet apparatus with 3 1 of distilled n-hexane for
12 h. After filtration and vacuum evaporation, 25 g of
dried n-hexane extract were obtained, the main
constituents thereof being lipophilic lignans, sterols
and pigments . The extract was a grey-brown paste which
was insoluble in water and methanol and soluble in
ethyl acetate.
Example 2:
Preparation of a dried methanol extract
(fraction 2; lot No.: 9810M)
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The remaining plant residue insoluble in
n-hexane from Example 1 was successively extracted with
3 1 of distilled methanol in a Soxhlet apparatus for
24 h. After filtration and vacuum evaporation, 50 g of -
dried methanol extract were obtained. The main con-
stituents were flavonoids, oligomeric gallotannins and
phenolcarboxylic acid. The dark-brown powder was
insoluble in water and almost completely soluble in
methanol.
Example 3:
Preparation of an aqueous supernatant
(fraction 3; lot No.: 9810Ws)
The methanol-insoluble plant residue (about
375 g) remaining after methanol extraction (see
Example 2) was infused with 2.5 1 of hot distilled
water and then macerated cold (+4°C) for 12 h. The warm
water extract was filtered and then 2.5 1 of ethanol
(100 (= 1:1)) were added dropwise in order to obtain a
precipitate of the high molecular weight disaccharides
and glycoproteins, which were then separated by ultra-
centrifugation at 7500 rpm. The lyophilized supernatant
phase afforded 15 g of dry material. The main
constituents were oligomeric gallotannins and other
water-soluble polymers. The result was a reddish-brown
powder which was soluble in water and insoluble in
organic solvent.
Example 4:
Preparation of a water precipitate
(fraction 4; lot No.: 9810pp)
The ethanol-precipitated and centrifuged poly-
meric portions from Example 3 were dissolved in hot
water and lyophilized. 5 g of extract are obtained
starting from 450 g of crude powder. The main con-
stituents are high molecular weight polysaccharides and
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glycoproteins. The resulting product was a brown powder
which was insoluble in water.
Example 5:
Preparation of a chlorophyll-free methanol crude
extract
(fraction 5; lot No.: 9901Mcf; P1159)
100 g of Phyllanthus powder from the herb were
extracted with 500 ml of distilled methanol in a
Soxhlet apparatus for 12 h. Filtration and vacuum
evaporation resulted in 15 g of dried extract, which
was dissolved in 300 ml of a hot mixture of distilled
water and methanol in the ratio 1:1. The solution was
reduced to half the volume on a water bath at 80°C,
stirring occasionally. The oily precipitate was removed
by hot (80°C) filtration through cellulose paper. Hot
distilled water (80°C) was added to the filtrate to
make up to 300 ml, followed by renewed filtration.
Lyophilization of the filtrate afforded about 10 g of
dry methanol extract. This had the appearance of a
brown paste and was soluble in methanol.
Example 6:
Preparation of a chlorophyll-free water extract
(fraction 6; lot No.: 9901Wcf)
50 g of Phyllanthus powder from the herb were
extracted with 500 ml of distilled water on a water
bath at 80-100°C for 1 h, stirring occasionally. The
hot solution was filtered through a cellulose paper.
100 ml of distilled methanol were added to the filtrate
(about 400 ml). The mixture was evaporated to half the
volume on a water bath at 80°C, stirring occasionally.
The oily precipitate was removed by hot filtration
(80°C) through cellulose paper. Lyophilization of the
filtrate afforded 3 g of dried water extract. This
extract was a reddish-brown powder which was soluble in
methanol.
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Example 7:
Radical scavenger experiment with DPPH
7 different concentrations of an extract
according to the invention called P11599 from Example 5
were investigated for their ability to trap free
radicals in a radical scavenger experiment. This was
done by measuring the change in colour between a stable
free radical DPPH (1,1-diphenyl-2-picrylhydrazyl) and
the relevant nonradical 1,1-diphenyl-2-picrylhydrazine
at 515 nm. This entailed incubating serial dilutions of
the test substances in DMSO and duplicate determina-
tions with a DPPH solution in methanol at 37°C for
30 min and measuring the change in colour. The SC50,
the concentration of sample at which 50~ of the DPPH
free radicals are trapped, was determined from the
results. DMSO was used as negative control and ascorbic
acid as positive control and these were measured - as
was Cc-tocopherol too. Determination of the SC50 values
gave 6.2 ~g/ml for P11599, 10 ~M for ascorbic acid and
18 ~.M for oc-tocopherol (see Figs. 1-3). As is evident
from the plots and results, P11599 was a better free
radical scavenger than oc-tocopherol and as good as
ascorbic acid.
Example 8:
Radical scavenger experiment with MTT
MTT (3-[4,5-dimethylthiazol-2-thiazol-2-yl]
2,5-diphenyltetrazolium bromide) was incubated in a
concentration of 10.6 mM at 37°C for 1 h with various
concentrations of an extract P11599 according to the
invention from Example 5 and with ascorbic acid as
reference, and the change in absorption due to the
action of the samples was determined by photometry. The
result shows an extremely high antioxidant potential of
P11599 similar to that of the relatively strong
reducing agent ascorbic acid (see Figs 4 and 5).
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Example 9:
Radical scavenger experiment with cytochrome c
Cytochrome c was incubated in a concentration
of 150 ~.M at 37°C for 0.5 h with various concentrations
of an extract P11599 according to the invention from
Example 5 and with ascorbic acid as reference, and the
change in the absorption due to the action of the
samples was determined by photometry. The result shows
an extremely high antioxidant potential of P11599
similar to that of the relatively strong reducing agent
ascorbic acid (see Figs 6 and 7).
Example 10:
Radical scavenger experiment with XTT/PMS
XTT/PMS (sodium 3,3'-[1-[(phenylamino)carbonyl]-
3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzenesulphonic
acid hydrate/phenazine methosulphate) was incubated in
a concentration of (500 (aM/0.21 ~M) at 37°C for 1 h
with various concentrations of an extract P11599
according to the invention from Example 5 and with
ascorbic acid as reference, and the change in absorp-
tion due to the action of the samples was determined by
photometry. The result shows an extremely high anti-
oxidant potential of P11599 similar to that of the
relatively strong reducing agent ascorbic acid (see
Figs 8 and 9).
Example 11:
Measurement of the cytotoxic effect and influence on
reducing capacity of the cells
The cytotoxic effect of an extract P11599
according to the invention from Example 5 was tested in
various concentrations on cultivated rat hepatocytes in
accordance with the experimental protocol of
Gebhardt R. (1997) Toxicol. Appl. Pharmacol. 144, 279-
286. No cytotoxic effect on hepatocytes was detectable
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- measured by the MTT absorption [~] - up to a
concentration of 1 mg/ml (Fig. 10). A further
surprising result shown by the rise in the curve in
this experiment was that the effect of the extract _
according to the invention was in fact to increase the
reductive capacity of the cells, which corresponds to
an increase in the reducing capacity for maintaining
the glutathione level (Fig. 10).
Example 12:
Measurement of the reduction of smooth muscle alpha-
actin (SMA) expression
Resting hepatic stellate cells were obtained
from a rat liver by perfusing the rat liver in situ
with collagenase and Pronase. The hepatic stellate
cells (HSC) were purified from the resulting cell
suspension by a density gradient with NycodenzTM. The
isolated HSC were then taken in cell culture (resting,
non-activated phenotype). Under standard cultivation
conditions in nutrient culture medium (DMEM, 18~ fetal
calf serum, usually purchasable from Sigma,
Deisenhofen, Germany) there is spontaneous activation
of the HSC (activated phenotype). For further
activation, the HSC were passaged in cell culture.
These cells were characterized morphologically and
immunohistochemically as myofibroblastic HSC.
To carry out the actual series of tests,
Phyllanthus extracts according to the invention (25~
ethanol LAT No. 02700514, 50~ ethanol LAT No. 0271614,
75~ ethanol LAT No. 0272514) dissolved in DMSO were
added in concentrations of 20 ~,g/ml, 60 ~,g/ml and
200 ~.g/ml to the nutrient culture medium of the
activated HSC. The treated HSC were then incubated in
nutrient culture medium for four days. After harvesting
the HSC, total cellular RNA were isolated by
conventional methods, and the concentration and quality
thereof was determined by spectrophotometry and by
CA 02372220 2001-10-26
- 18 -
agarose gel electrophoresis. Expression of the SMA mRNA
was detected by the Northern blot method known in the
state of the art.
With all the tested Phyllanthus extracts,
addition of 200 ~.g/ml led to distinct inhibition of the
growth of HSC in cell culture and a considerably
smaller amount of isolated total cellular RNA. In the
Northern blot there was likewise observed to be a
distinct reduction in the expression of the SMA mRNA,
which was evident on use of the 50~ ethanol extract at
a concentration as low as 60 ~,g/ml.
Example 13:
Measurement of the reduction of the expression of LPS
induced nitric oxide synthase (NOS), of the induced NOS
protein (iNOS) and of the cyclooxygenase (COX-2)
protein
Nitric oxide (NO) production effected by NOS
was measured using macrophages which were incubated in
RPMI nutrient culture medium with 10~ fetal calf serum
(usually purchasable from Sigma, Deisenhofen, Germany).
The cells were then stimulated with LPS (1 ug/ml) and
incubated with or, as a control, without Phyllanthus
extracts for 24 h. The NO concentration was determined
by the Griess assay (Kiemer, A. and Vollmar, A. (1998),
J. Biol. Chem. 273(22): 13444-13451).
NO production was effectively reduced with the
tested Phyllanthus extracts, especially by a hexane
extract (LAT No. 01600514) at a concentration
12.5 ug/ml and an ethanol/water extract (LAT No.
00690514) in a concentration of 250 ug/ml. A reduction
in the LPS-induced iNOS and COX-2 protein expression
was found at concentrations of 125 ~.g/ml hexane extract
and ethanol/water extract (Figs 11-14).
